Antennas, such as slot antennas and patch antennas, are employed in a wide variety of wireless devices, such as cell phones, pagers, wireless personal digital assistants, access points and other wireless local area network (WLAN) components, and the like. One common goal for the design of such wireless devices is to minimize the product dimensions. Another common goal is to incorporate some or all of the components into an integrated circuit (IC) package. However, due to their physical properties, conventional slot antennas inhibit the full achievement of these goals.
The resonant frequency (also referred to as the radiation frequency) of a traditional slot antenna is inversely proportional to the length of its slot. However, when slot antennas are employed in small structures, it has been observed that the resonant frequency of such slot antennas instead become inversely proportional to the area of the resonant cavity of the slot antenna. Thus, to achieve a lower resonant frequency the dimensions of the slot antenna must be increased in the x-y plane of the slot antenna. Due to the relatively low wireless frequencies employed in common wireless communication standards, this inversely proportional relationship between frequency and cavity area often prevents slot antennas from being incorporated into devices, or even if incorporated, from being integrated into an IC package. To illustrate, a conventional slot antenna generally is required to have a resonant cavity with an area that is at around 900 mm2 (1.395 in2) to have a resonant frequency in the 2.4 gigahertz (GHz) frequency range, a size that is prohibitive in many applications.
Accordingly, an improved slot antenna would be advantageous.